Known air-dryers of the kind which operate in accordance with the above, in which the rotor normally rotates at a speed of about 25 rev./h, do not effectively utilize the supplied energy and therefore incur high operation costs. Such air-dryers are also large and heavy, and therefore expensive.
The air-dryers are also relatively complicated structurally, and consequently are expensive as a whole and difficult to dismantle, for instance for servicing and maintenance purposes.
Present-day air-drying or dehumidifying systems are also constructed from materials which render the useful life of such systems unsatisfactory.
The unsatisfactory efficiency of present-day air drying apparatus is due, inter alia, to the fact that the regenerating battery is located at some considerable distance from the rotor. The regeneration air--which normally has a temperature of 110.degree.-120.degree. C.--is therefore incapable of extracting moisture effectively, particularly moisture which is captured in the nooks and crannies of those rotor-parts which are located in the region of the low-pressure side of the rotor, where the moisture is most difficult to extract.
Also known to the art are air-dryers or dehumidifiers of the kind which include a moisture-adsorbing rotor provided with drive means, two fans driven by a common motor, of which one fan is intended for process air and the other fan intended for regeneration air, and filters for filtering the two air-flows.
This known drying apparatus is divided into five sections, placed one above the other. The requisite electrical equipment is housed in the lid or cover of the dryer, together with the rotor drive-motor The two fans, the motor which is common to the fans, and the filters are housed in the second and third sections respectively. The next lowest section houses a distribution chamber operative to distribute process-air and regeneration-air, together with a heating battery. The actual rotor itself is housed in the bottom section, with the rotor in a horizontal, i.e. with a vertical axis. Subsequent to regenerating the rotor in the lowermost section of the dryer, the wet air and the dry air are led away from said section in mutually different directions.
This apparatus is also ineffective, since that part of the rotor where the moisture is captured most effectively, i.e. is the most difficult to extract, is not regenerated at a sufficiently high level of temperature.
Other examples of the present state of this art are to be found in GB-A-2165465 (Munter Rotair) and SE-B-429301 (Munters).